Synthetic resin filler cap

ABSTRACT

The bottle cap unit ( 1 ) of this invention comprises an inner cap ( 2 ), which is tightly fitted to the bottleneck ( 24 ) to form a pour spout, and an outer cap ( 15 )  
     , which is detachably screwed on or off the inner cap ( 2 ) to close or open the pour spout. The first locking part ( 5 ) is disposed on the outer wall of the attaching cylinder ( 3 ) of the inner cap ( 2 ). The second locking part ( 23 ) is disposed on the locking cylinder ( 22 ), which is connected to the outer cylinder ( 20 ) of the outer cap ( 15 ) via the breaking pieces ( 21 ). This second locking part ( 23 ) is engaged from underside with the first locking part ( 5 ) to lock the outer cap ( 15 ). The attachment of the inner cap ( 2 ) to the bottleneck ( 24 ) is set at such a strength that allows the inner cap ( 2 ) to be manually snapped out of the bottleneck ( 24 ). In this configuration, the bottle cap unit ( 1 ) can be easily snapped out of the bottleneck ( 24 ) for separate collection.

TECHNICAL FIELD

[0001] This invention refers to a synthetic resin bottle cap unit havinga tamperproof function, which comprises an inner cap, fitted to thebottleneck and provided with a pour spout for the liquid content, and anouter cap to open or close the pour spout of this inner cap, wherein thebottle cap unit is configured so that separate collection isadvantageously carried out at the time of waste disposal.

BACKGROUND OF THE INVENTION

[0002] There is a need for separately collecting synthetic resinproducts for efficient reutilization of discarded synthetic resinbottles and containers. As a means of such separate collection, there isa prior-art technology disclosed in the Official Gazette of Japanesepatent application laid open No. 1999-255251, which refers to a bottlecap fitted to the neck of a bottle or container to form a pour spout andwhich shows a mechanism that enables the bottle cap to be readilyremoved from the bottle when it is discarded.

[0003] The bottle cap of that prior-art invention comprises an inner caphaving an attaching cylinder, which is tightly fitted around thebottleneck and locked by climbing over the neck to form a pour spout,and an outer cap, which is detachably screwed on or off the inner cap toclose or open the pour spout. The locking recession corresponding to thefirst locking part is integrally formed on the outer circumference ofthe portion having locking engagement with the bottleneck, and thislocking recession is disposed on the lower part of the attachingcylinder of the inner cap and is provided with plural, verticalexpanding slots. A locking ring having the second locking part isconnected via the plural breaking pieces to the lower part of the outercylinder of the outer cap that is fitted around this attaching cylinder.The second locking part locks with the first locking part of theattaching cylinder in a manner that the second one is unable to climbover the first one in the upward direction but is able to climb over thebottleneck in the downward direction by the forced pulling operation.

[0004] In this prior art, tamper-proof action is displayed by theseparation of the locking ring from the outer cylinder of the outer cap.The fitting of the inner cap to the bottleneck is tightly maintained bythe locking action of the locking ring to lock with the lower portion ofthe attaching cylinder. The inner cap can be readily removed from thebottleneck by breaking the locking ring away in the downward directionfrom the lower end of the attaching cylinder.

[0005] However, in this prior art, the lower portion of the attachingcylinder of the inner cap is in an exposed state, which has caused aproblem in that the inner cap can be easily broken away from thebottleneck by inserting a hard tip of, e.g., a screwdriver, into the gapbetween the attaching cylinder and the bottleneck and picking the innercap out of the bottleneck.

[0006] It is necessary in this prior art to form both of the portionhaving a bottleneck-locking function and the locking recessioncorresponding to the first locking part that locks the outer cap,integrally in the lower portion of the attaching cylinder of the innercap. This first locking part is engaged with the second locking part soas to hinder the locking ring from rising upward and from moving freely,but to permit the ring to be moved forcibly. Thus, another problemarises here in that the structure becomes all the more complicated.

[0007] In addition, after the breaking pieces have been broken, there isno visible change in the relationship of the locking ring with the lowerportion of the attaching cylinder because the pieces remain at the sameposition in the lower portion of the attaching cylinder. Before andafter the breakage, there is no change in the position of the lockingring. It is difficult, therefore, to recognize the breakage of thebreaking pieces from the looks of them. For this reason, still anotherproblem brought about was that sometimes the tamper-proof effect has notbeen fully demonstrated.

SUMMARY OF THE INVENTION

[0008] This invention has been made to solve these problems found in theabove-described prior art. An object of this invention is to make itimpossible to break open the inner cap unjustly from the bottleneck bymeans of a hard tool. Another object is to give the bottle cap unit asimple structure. Still other objects are to demonstrate a cleartamper-proof effect, to enhance the safety of bottles as commercialproducts, and to reduce the production cost reasonably.

[0009] In the first embodiment of this invention, there is provided asynthetic resin bottle cap unit. It comprises an inner cap having anattaching cylinder that is tightly fitted around bottleneck, and lockedby climbing over the neck, to form a pour spout. It also comprises acylindrical, flat-topped, outer cap, which is detachably screwed on oroff the inner cap to close or open the pour spout. This attachingcylinder of the inner cap is provided with the first locking partdisposed on the outer cylindrical wall of the portion opposed to thebottleneck-locking part. The outer cap is provided with an outercylinder and a locking cylinder disposed in the lower portion of theouter cylinder and integrally connected thereto through multiplebreaking pieces. The locking cylinder has a bore diameter larger thanthe outer diameter of this neck ring, and is provided with the secondlocking part that goes into the locking engagement from underside withthe first locking part under the condition that the outer cap has beenscrewed on the bottleneck. In this configuration, attachment of theinner cap to the bottleneck is set at such a strength that the inner capcan be manually snapped out of the bottle neck, and yet that strength iswithin a range enough to keep the inner cap fitted tightly to thebottleneck but not to allow to inner cap to be slipped out of thebottleneck because of a water-hammer force of the liquid content nor toallow the inner cap to move freely around the bottleneck.

DISCLOSURE OF THE INVENTION

[0010] Under the condition that this synthetic resin bottle cap unit hasbeen fitted to the bottleneck, the outer cap closes the pour spout ofthe inner cap now that the outer cap has been screwed on the inner cap.At that time, the outer cap is fitted around the attaching cylinder ofthe inner cap, and the locking cylinder allows its second locking partto enter the locking engagement from underside with the first lockingpart, which is formed on the outer circumference of the attachingcylinder of the inner cap.

[0011] When the outer cap is turned in order to screw it off the innercap, the locking cylinder is unable to ascend because of the lockingengagement between the first and second locking parts, unlike thecombination of the main cylinder and the outer cylinder of the outercap, which continues to ascend. As a result, the breaking pieces arebroken at one time of this ascent.

[0012] Once the breaking pieces have been broken, the locking cylinderfalls downward due to its own weight, and its position changes to alarge extent before and after the breakage. Because of this largepositional change in the locking cylinder, it becomes possible to knowclearly that the breaking pieces have been surely broken and todemonstrate the tamper-proof function.

[0013] After the breakage, the locking cylinder falls easily andsmoothly down to the limit of fall, with no interference from the neckring because the locking cylinder has a bore diameter larger than theouter diameter of the neck ring.

[0014] When the bottle cap unit is separately collected from thebottleneck, the inner cap can be forcibly snapped out of the bottleneckby grasping the inner cap with a hand, acting a wrenching force, anddeflecting and deforming the attaching cylinder in the direction inwhich the diameter is widened.

[0015] At that time, if the combination of the main cylinder and theouter cylinder of the outer cap is screwed on the inner cap that hasbeen fitted to the bottleneck, the bottle cap unit can be grasped firmlywith a hand under a favorable condition.

[0016] After the inner cap has been snapped out of the bottleneck, thelocking cylinder is taken out of the bottleneck to complete the separatecollection of the bottle cap unit.

[0017] Before the breaking pieces are broken, the locking cylinder ofthe outer cap remains fitted around the attaching cylinder of the innercap. In this state, the attaching cylinder is inhibited from wideningthe diameter and deforming the shape. As a result, the inner cap remainsfitted stably and firmly to the bottleneck.

[0018] In the second embodiment of this invention, there is providedanother synthetic resin bottle cap unit. It comprises an inner caphaving an attaching cylinder that is tightly fitted around bottleneck,and locked by climbing over the neck, to form a pour spout. It alsocomprises a cylindrical, flat-topped, outer cap, which is detachablyscrewed on or off the inner cap to close or open the pour spout. Thisattaching cylinder of the inner cap is provided with the first lockingpart disposed on the outer cylindrical wall of the portion opposed tothe bottleneck-locking part and also with a hooking edge slightlyprojected laterally from the lower edge of the attaching cylinder. Theouter cap is provided with an outer cylinder and a locking cylinderdisposed in the lower portion of the outer cylinder and integrallyconnected thereto through multiple breaking pieces. The locking cylinderhas a bore diameter larger than the outer diameter of this neck ring,and is provided with the second locking part that goes into the lockingengagement from underside with the first locking part and also into alight locking engagement from upper side with the hooking edge under thecondition that the outer cap has been screwed on the bottleneck. In thisconfiguration, attachment of the inner cap to the attaching cylinder isset at such a strength that the inner cap can be manually snapped out ofthe bottle neck, and yet that strength is within a range enough to keepthe inner cap fitted tightly to the bottleneck but not to allow theinner cap to move freely around the neck.

[0019] Once the breaking pieces have been broken, the locking cylinderfalls downward due to its own weight until the second locking part isengaged from upper side with the hooking edge of the inner cap, and itsposition changes to a large extent before and after the breakage.Because of this large positional change in the locking cylinder, itbecomes possible to know clearly that the breaking pieces have beensurely broken and to demonstrate the tamper-proof function.

[0020] Before the breaking pieces are broken, the locking cylinder ofthe outer cap is fitted around the lower portion of the attachingcylinder of the inner cap. Since, therefore, the attaching cylinder ofthe inner cap is unable to widen its diameter and deform its shapefreely, tight attachment of the inner cap to the bottleneck is stablymaintained.

[0021] When the bottle cap unit is separately collected from thebottleneck, the inner cap can be forcibly snapped out of the bottleneckby grasping the inner cap with a hand, acting a wrenching force,unlocking the second locking part from the weak locking engagement withthe hooking edge, allowing the locking cylinder to fall, and thenforcibly wrenching the inner cap away from the bottleneck.

[0022] At that time, if the combination of the main cylinder and theouter cylinder of the outer cap is screwed on the inner cap that hasbeen fitted to the bottleneck, the bottle cap unit can be grasped firmlywith a hand under a favorable condition.

[0023] After the inner cap has been wrenched away, the locking cylinderis taken out of the bottleneck to complete the separate collection ofthe bottle cap unit.

[0024] The third embodiment of this invention includes the configurationof the first or second embodiment, and also comprises that the strengthof attachment of the inner cap to the bottleneck is set by means of thethickness of the attaching cylinder of the inner cap.

[0025] In this embodiment, the thinner the attaching cylinder of theinner cap is, the more easily it becomes susceptible to deflectivedeformation by external force in the diameter-widening direction. On theother hand, the thicker the attaching cylinder is, the more difficult itis to deform the attaching cylinder. Thus, by setting this thicknessproperly, it is possible to set the strength of attachment of the innercap to the bottleneck within a reasonable range without adding anyspecial structure.

[0026] The fourth embodiment of this invention includes theconfiguration of the first or second embodiment, and also comprises thatthe strength of attachment of the inner cap to the bottleneck is set bymeans of the expanding slots disposed at least in the lower portion ofthe attaching cylinder.

[0027] In this embodiment, shape parameters, such as the number ofexpanding slots and the slot length, determine the extent to which theattaching cylinder is deformed by the deflection caused by an externalforce. Thus, by using the slot number and length, it is possible to setthe strength of attachment of the inner cap to the bottleneck preciselywithin a reasonable range.

[0028] The fifth embodiment of this invention includes the configurationof the first, second, third or fourth embodiment, and also comprisesthat the locking cylinder of the outer cap has a height ranging from thelevel of the first locking part to the neck ring of the bottleneck.

[0029] Because, in this embodiment, the locking cylinder of the outercap has a height ranging from the level of the first locking part of theattaching cylinder to the neck ring of the bottleneck, this lockingcylinder covers the space between the neck ring of the bottle and thelower edge of the attaching cylinder of the inner cap. Thisconfiguration prevents the bottle cap unit from being unjustly pickedout of the bottleneck by inserting a hard tool, such as the blade of ascrewdriver, into this space.

[0030] The sixth embodiment of this invention includes the configurationof the first, second, third, fourth, or fifth embodiment, and alsocomprises that the first locking part of the inner cap has a simpleridge structure.

[0031] In this embodiment, the structure of the first locking part isquite simplified. A major portion of the attachment to the bottleneckhas a large thickness all the more because the first locking part isdisposed in this portion. This makes serves to lessen the thickness ofother portions of the attaching cylinder.

[0032] The seventh embodiment of this invention includes theconfiguration of the first, second, third, fourth, fifth, or sixthembodiment, and also comprises that the second locking part is acircumferential ridge, which is disposed on the inner surface of thelocking cylinder of the outer cap and is capable of climbing over thefirst locking part.

[0033] In this embodiment, the second locking part is a circumferentialridge of a simple shape. Because of its simple structure, thebottleneck, the inner cap, and the outer cap can be attached to oneanother with precision. It becomes easy, therefore, to mold the outercap, which requires precise molding.

[0034] The eighth embodiment of this invention includes theconfiguration of the first, second, third, fifth, sixth, or seventhembodiment, and also comprises that either or both of the first lockingpart and the second locking part have an intermittent, circumferentialridge structure.

[0035] When, in this embodiment, either or both of the first lockingpart and the second locking part have an intermittent, circumferentialridge structure, the thick, first or second locking part can be readilyexpanded in the radial direction. Thus, it becomes easy to attach theinner cap to the bottleneck in the state in which the outer cap has beenfitted in advance to the inner cap.

[0036] The intermittent, circumferential ridge structure herein refersto a circumferential ridge structure in which the ridge is cut off attwo opposite places or at multiple, equally spaced places.

[0037] The ninth embodiment of this invention includes the configurationof the first, second, third, fourth, fifth, or sixth embodiment, andalso comprises that the second locking part consists of multiple,flexible flaps, which are capable of elastic displacement to extend theflaps obliquely upward and inward from the locking cylinder of the innercap.

[0038] In this embodiment, the second locking part consisting offlexible flaps makes it easy to climb over the first locking part of theinner cap and to enter the locking engagement from underside with thefirst locking part without giving damage to the breaking pieces that areapt to be broken.

[0039] The tenth embodiment of this invention includes the configurationof the first, second, third, fourth, fifth, sixth, seventh, eighth, orninth embodiment, and also comprises that a space enabling the peripheryof a coin to enter therein is formed between the neck ring and the loweredge of the attaching cylinder of the inner cap.

[0040] In this embodiment, it is possible even for a weak person to snapthe inner cap easily out of the bottleneck at the time of wastedisposal, using a hard tool found near at hand, such as a coin.

[0041] The eleventh embodiment of this invention includes theconfiguration of the first, second, third, fourth, fifth, sixth,seventh, eighth, ninth, or tenth embodiment, and also comprises that theminimum bore diameter of the locking cylinder including the secondlocking part is set at a value larger than the outer diameter of theneck ring of the bottleneck.

[0042] In this embodiment, after the breakage of the breaking pieces,the locking cylinder falls down to the limit of fall for a sufficientheight without interference of the neck ring. Thus, the tamper-prooffunction is clearly demonstrated, and this fall definitely exposes thespace between the attaching cylinder and the neck ring.

[0043] The twelfth embodiment of this invention includes theconfiguration of the first, second, third, fourth, fifth, sixth,seventh, eighth, ninth, tenth, or eleventh embodiment, and alsocomprises that the inner cap is colored differently from the outer cap.

[0044] In this embodiment, the breaking pieces are broken, and thelocking cylinder of the outer cap falls to the limit of fall. In thisstate, the lower portion of the attaching cylinder of the inner caphaving a color different from the color of the outer cap becomes visiblebeneath the outer cap. This color difference demonstrates thetamper-proof function more effectively.

[0045] The thirteenth embodiment of this invention includes theconfiguration of the first, second, third, fourth, fifth, sixth,seventh, eighth, ninth, tenth, eleventh, or twelfth embodiment, and alsocomprises that the pour spout of a pull-open type is formed in the innercap to guide the flow of the liquid content, and is opened by pulling upa pull ring and the like to break and remove a lid portion, with thislid portion being zoned by a breaking groove that forms a closed loopsurrounding the sealing lid, which constitutes the bottom of the pourspout.

[0046] In this embodiment of this invention, the bottle can be keptsealed securely and firmly until the pour spout is opened.

BRIEF DESCRIPTION OF THE DRAWINGS

[0047]FIG. 1 is an entire perspective view showing the bottle cap unitin the first embodiment of this invention before the unit is assembled.

[0048]FIG. 2 is a partial, front elevational view showing the right halfof the bottle cap unit in the first embodiment of FIG. 1 in alongitudinal section before the outer cap is screwed off.

[0049]FIG. 3 is a partial, front elevational view showing the right halfof the bottle cap unit in the first embodiment of FIG. 1 in alongitudinal section after the outer cap has been screwed off.

[0050]FIG. 4 is an entire perspective view showing the bottle cap unitin the second embodiment of this invention before the unit is assembledFIG. 5 is a partial, front elevational view showing the right half ofthe bottle cap unit in the second embodiment of FIG. 4 in a longitudinalsection before the outer cap is screwed off.

[0051]FIG. 5 is a partial, front elevational view showing the right halfof the bottle cap unit in the second embodiment of FIG. 4 in alongitudinal section before the outer cap is screwed off.

[0052]FIG. 6 is a partial, front elevational view showing the right halfof the bottle cap unit in the second embodiment of FIG. 4 in alongitudinal section before the outer cap has been screwed off.

[0053]FIG. 7 is an entire perspective view showing the inner cap in thethird embodiment of this invention.

[0054]FIG. 8 is a partial, front elevational view showing the right halfof the inner cap in the third embodiment of FIG. 7 in a longitudinalsection.

[0055]FIG. 9 is an entire perspective view showing the inner cap in thefourth embodiment of this invention.

[0056]FIG. 10 is a partial, front elevational view showing the righthalf of the bottle cap unit in the fourth embodiment of FIG. 9 in alongitudinal section before the outer cap is screwed off.

[0057]FIG. 11 is a partial, front elevational view showing the righthalf of the bottle cap unit in the fifth embodiment of this invention ina longitudinal section before the outer cap is screwed off.

[0058]FIG. 12 is a partial, front elevational view showing the righthalf of the bottle cap unit in the fifth embodiment of this invention ina longitudinal section before the outer cap has been screwed off.

[0059]FIG. 13 is a partial, front elevational view showing the righthalf of the bottle cap unit in the sixth embodiment of this invention ina longitudinal section before the outer cap is screwed off.

[0060]FIG. 14 is a partial, front elevational view showing the righthalf of the bottle cap unit in the sixth embodiment of FIG. 13 in alongitudinal section before the outer cap has been screwed off.

PREFERRED EMBODIMENTS OF THE INVENTION

[0061] This invention is further described with respect to preferredembodiments, now referring to the drawings.

[0062] First Embodiment

[0063] The bottle cap unit 1 of this invention comprises the inner cap 2and the outer cap 15, both made of a polypropylene resin or alow-density polyethylene resin.

[0064] As shown in FIGS. 1 and 2, the inner cap 2 has a configurationcomprising:

[0065] the attaching cylinder 3, which is fitted around the bottleneck24 and is formed at a height that enables the periphery of a coin toenter the gap between the neck ring 26 and the lower portion of thisattaching cylinder 3;

[0066] the threaded cylinder 8 having a thread ridge notched on theouter wall thereof and standing from the inner ledge 7, which isconnected to the upper portion of the attaching cylinder 3;

[0067] the pour spout 11 of a bottomed cylindrical shape widened at thetop end like a trumpet and connected to the threaded cylinder 8 viainward brim 10; and

[0068] the lid portion 13 provided with a pull ring and the like andzoned by a breaking groove 14 that forms a closed loop surrounding asealing lid 12, which constitutes the bottom of the pour spout 11.

[0069] The attaching cylinder 3 to be fitted around the bottleneck 24comprises a portion having a locking function for the bottleneck 24.This portion is represented by a stop ridge 4, which is disposed on thelower inner wall of the attaching cylinder 3 and climbs over thecircumferential, bottleneck-locking ridge 25 disposed on the outer wallof the top portion of the bottleneck 24. The first locking part 5 of acircumferential ridge is formed on the outer wall of the attachingcylinder 3 at a position higher than the adjacent stop ridge 4 and at asimilar position that the bottleneck-locking ridge 25 takes.

[0070] The strength of attachment of the inner cap 2 to the bottleneck24 is set by means of the thickness of the attaching cylinder 3 at sucha level that the inner cap 2 can be manually snapped out of thebottleneck 24 under the condition that the locking cylinder 22 has beendetached from the outer cap 15, and yet that strength is within a rangeenough to keep the inner cap 2 fitted tightly to the bottleneck 24 butnot to be slipped out of the bottleneck 24 because of a water-hammerforce of the liquid content, not to allow the inner cap 2 to move freelyaround the neck, and not to be slipped out when the lid portion 13 isbroken and removed by pulling up the pull ring. If the stop ridge 4 ofthe inner cap 2 has an intermittent ridge structure, it is possible toweaken the strength of attachment of the attaching cylinder 3 to thebottleneck 24 so that the inner cap 2 can be snapped out of thebottleneck 24.

[0071] Sealing cylinder 9 hanging from the threaded cylinder 8 allowsthe inner cap 2 to be fitted tightly to the bottleneck 24 by making thebottleneck 24 fitted into the gap between the sealing cylinder 9 and theattaching cylinder 3.

[0072] The outer cap 15 has a configuration comprising:

[0073] a top plate 16 from which a stopper guide 18 is suspendeddownward for tight fitting into the pour spout 11;

[0074] a main cylinder 17, which is screwed on the threaded cylinder 8and is suspended from the periphery of the top plate 16;

[0075] an outer cylinder 20, which is beneath the main cylinder 17, isfitted around the attaching cylinder 3, and is suspended from the edgeof the outward brim 19; and

[0076] a locking cylinder 22, which is connected to the lower portion ofthis outer cylinder 20 through multiple, easy-to-break breaking pieces21 and is provided with a circumferential ridge 27 serving as the secondlocking part 23, which is disposed on the inner surface of this lockingcylinder 22, and is engaged with the first locking part 5 by climbing itover and locking therewith from underside.

[0077] If the first locking part 5 of the inner cap 2 has anintermittent, circumferential ridge structure, or if the second lockingpart 23 of the outer cap 15 has an intermittent, circumferential ridge27, or both of the first and second locking parts have an intermittent,circumferential ridge structure, then the first locking part 5 of theinner cap 2 or the second locking part 23 of the outer cap 15 is apt towiden the diameter even if it is thick. In such a case, the inner cap 2can be easily fitted to the bottleneck 24 in the state in which theouter cap 15 has been screwed on the inner cap 2.

[0078] The locking cylinder 22 has a minimum bore diameter larger thanthe outer diameter of the neck ring 26 even if the bore diameterincludes the circumferential ridge 27. In the unopened state shown inFIG. 2, the circumferential ridge 27 is contacted with the first lockingpart 5, and the lower edge of the locking cylinder 22 faces the side ofthe neck ring 26. When the breaking pieces 21 are broken, the lockingcylinder falls downward without interference of the neck ring 26.

[0079] In this unopened state, the locking cylinder 22 keeps back theattaching cylinder 3 from outside specifically with the circumferentialridge 27, and thereby prevents the attaching cylinder 3 fromindiscriminate outward expansion and deformation, thus achieving andmaintaining stable fitting of the inner cap 2 to the bottleneck 24.

[0080] The locking cylinder 22 has a height ranging from the level ofthe first locking part 5 to the neck ring 26, covers the gap formedbetween the attaching cylinder 3 and the neck ring 26, and thereby makesit impossible to pick the inner cap 2 unjustly out of the bottleneck 24.

[0081] As shown in FIG. 3, when the breaking pieces 21 are broken, thelocking cylinder 22 falls below the neck ring 26 due to its own weight.

[0082] When the liquid content is to be poured out for the first time,the outer cap 15 is screwed off the inner cap 2, and the pull ring ispulled up to break and remove the lid portion 13. The thickness of theattaching cylinder 3 is set at such a level that the inner cap 2 nevercomes off the bottleneck 24 at the time of breakage and removal of thelid portion 13. Therefore, it is difficult for the attaching cylinder 3to deform and widen largely in the radial direction. Because of thisdifficulty, the stop ridge 4 is prevented from climbing over thebottleneck-locking ridge 25, and as a result, the inner cap 2 isprevented from coming off the bottleneck.

[0083] In the meantime, when the bottle cap unit 1 is separatelycollected from the bottleneck 24, a wrenching force is applied manuallyon the inner cap 2 under the condition that the outer cap 15 has beenscrewed on the inner cap 2. Since the thickness of the attachingcylinder 3 is set at such a level that the inner cap 2 can be snappedout of the bottleneck 24, the attaching cylinder 3 bends and deformsfully in the radial direction. Thus, it is possible even for a weakperson to snap the inner cap 2 easily out of the bottleneck 24.

[0084] When the bottle cap unit 1 is separately collected from thebottleneck 24, the inner cap 2, along with the outer cap 15 that hasbeen screwed on the inner cap 2, may be forcibly snapped out of thebottleneck 24, as described above. However, as shown in FIG. 3 by achain double-dotted line, the bottle cap unit 1 can be easily separatedfrom the bottleneck 24 by inserting the tip of a hard tool near at hand,such as the periphery of a coin, into the gap between the attachingcylinder 3 and the neck ring 26 and prying the attaching cylinder 3 openwith the coin in a manner to widen the diameter.

[0085] Second Embodiment

[0086] The second embodiment shown in FIGS. 4-6 includes theconfiguration of the first embodiment, and also comprises that thisattaching cylinder 3 to be fitted around the bottleneck 24 is providedwith a hooking edge 6, which is slightly projected laterally from thelower edge of the attaching cylinder 3 and is disposed in the lowerportion of the first locking part 5 of a circumferential ridgestructure.

[0087] The attachment of the inner cap 2 to the bottleneck 24 is set bymeans of the thickness of the attaching cylinder 3 at such a strengththat the inner cap 2 can be manually snapped out of the bottleneck 24,and yet that strength is within a range enough to keep the inner cap 2fitted tightly to the bottleneck 24 but not to allow the inner cap 2 tomove freely around the neck.

[0088] The outer cap 15 has a configuration comprising:

[0089] a top plate 16 from which a stopper guide 18 is suspendeddownward for tight fitting into the pour spout 11;

[0090] a main cylinder 17, which is screwed on the threaded cylinder 8and is suspended from the periphery of the top plate 16;

[0091] an outer cylinder 20, which is beneath the main cylinder 17, isfitted around the attaching cylinder 3, and is suspended from the edgeof the outward brim 19; and

[0092] a locking cylinder 22, which is connected to the lower portion ofthis outer cylinder 20 through multiple, easy-to-break breaking pieces21 and is provided with a circumferential ridge 27 serving as theridge-like second locking part 23, which is disposed on the innersurface of this locking cylinder 22 and is engaged with the firstlocking part 5 by climbing it over and locking therewith from underside,with this second locking part 23 also having a light locking engagementfrom upper side with the hooking edge 6.

[0093] The width of the circumferential ridge 27, i.e., the secondlocking part 23, in the vertical direction is adequately smaller thanthe length between the first locking part 5 and the hooking edge 6.Thus, the locking cylinder 22 is allowed to fall as much as possiblewhen the breaking pieces 21 are broken.

[0094] The locking cylinder 22 has a bore diameter larger than the outerdiameter of the neck ring 26. In the unopened state shown in FIG. 2, theupper portion of the locking cylinder 22 comes in contact with the firstlocking part 5, and the lower edge faces the side of the neck ring 26.The locking cylinder 22 keeps back the attaching cylinder 3 fromoutside, and thereby prevents the attaching cylinder 3 fromindiscriminate outward expansion and deformation, thus achieving andmaintaining stable fitting of the inner cap 2 to the bottleneck 24.

[0095] When the breaking pieces 21 are broken, the locking cylinder 22falls to the limit of fall, without interference of the neck ring 26,down to the position at which the locking cylinder 22 is stopped by thehooking edge 6, thus making sure that the locking cylinder 22 falls fromthe place where it has been before.

[0096] When the liquid content is to be poured out for the first time,the outer cap 15 is screwed off the inner cap 2 as shown in FIG. 6, andthe pull ring is pulled up to break and remove the lid portion 13. Atthat time, the circumferential ridge 27 of the locking cylinder 22 isengaged with the hooking edge 6 and remains fitted around the attachingcylinder 3. Therefore, it is difficult for the attaching cylinder 3 todeform and widen largely in the radial direction. Because of thisdifficulty, the stop ridge 4 is prevented from climbing over thebottleneck-locking ridge 25.

[0097] The minimum bore diameter of the locking cylinder 22 includingthe second locking part 23 is set at a value larger than the outerdiameter of the neck ring 26. Therefore, when the locking cylinder 22leaves the attaching cylinder 3 downward, the locking cylinder 22 fallsto the limit of fall, as shown in FIG. 6 by a chain double-dotted line,without interference of the neck ring 26, and can be separated withoutfail from the attaching cylinder 3.

[0098] Thus, the attaching cylinder 3 has such a thickness that theinner cap 2 can be snapped out of the bottleneck 24 manually. Expansionand deformation can take place under a manual wrenching force in thelower portion of the attaching cylinder 3, without interference of thelocking cylinder 22. Therefore, it is possible even for a weak person tosnap the inner cap 2 easily out of the bottleneck 24.

[0099] Similarly, when the locking cylinder 22 falls down to the limitof fall without interference of the neck ring 26, a gap is exposedbetween the neck ring 26 and the lower edge of the attaching cylinder 3.As shown in FIG. 6 by a chain double-dotted line, the bottle cap unit 1can be easily separated by inserting the tip of a hard tool near athand, such as the periphery of a coin, into the gap and wrenching theattaching cylinder 3 open in the radial direction.

[0100] Third Embodiment

[0101] The third embodiment shown in FIGS. 7 and 8 has a configurationthat the strength of attachment of the inner cap 2 to the bottleneck 24is set by the expanding slots 4 a, which are disposed in the lowerportion of the attaching cylinder 3 of the inner cap 2. The firstlocking part 5 of the inner cap 2 has an intermittent, circumferentialridge structure because of the expanding slots 4 a. In forming theexpanding slots 4 a, it is necessary to design the slots while givingconsideration to the number, length, and width of the slots, as well asthe entire bottle structure and the bottle usage. This is because theattachment of the inner cap 2 to the bottleneck 24 has to be set at aproper strength and because the strength has to be within a range enoughto be able to snap the inner cap 2 out of the bottleneck 24 by applyingonly a weak-wrenching force.

[0102] When the bottle cap unit 1 is separated and collected from thebottleneck 24, a wrenching force is applied manually on the inner cap 2under the condition that the outer cap 15 has been screwed on the innercap 2. In the presence of the expanding slots 4 a, only a weak-wrenchingforce is enough for the attaching cylinder 3 to bend and deform fully inthe radial direction so that even a weak person can snap the bottle capunit 1 easily out of the bottleneck 24.

[0103] Fourth Embodiment

[0104] The fourth embodiment shown in FIGS. 9 and 10 has a configurationthat the strength at which the inner cap 2 provided with the hook edge 6is attached to the bottleneck 24 is set by means of the expanding slots4 a disposed at least in the lower portion of the attaching cylinder 3.

[0105] When the bottle cap unit 1 is separated and collected from thebottleneck 24, only a weak-wrenching force is enough for the attachingcylinder 3 to bend and deform fully in the radial direction in thepresence of the expanding slots 4 a. Therefore, the bottle cap unit 1can be easily snapped out of the bottleneck 24 for separate collection.

[0106] Fifth Embodiment

[0107] In the fifth embodiment shown in FIGS. 11 and 12, the secondlocking part is disposed on the locking cylinder 22 of the outer cap 15,and consists of multiple, flexible flaps 28, which can be extendedobliquely upward and inward from the lower edge of the locking cylinder22.

[0108] The flexible flaps 28 are obtained by cutting out the lowerportion of the locking cylinder 22 to form multiple sections, which arebent inward into flaps at the height of the neck ring 26 so that theflaps 28 extend obliquely upward. The flexible flaps 28 may also bemultiple projections extending obliquely upward from the lower edge ofinner surface of the locking cylinder 22.

[0109] When the outer cap 15 is fitted to the inner cap 2, the flexibleflaps 28 are displaced as shown in FIG. 11. These flaps 28 climb overthe first locking part 5 smoothly without breaking the multiple,easy-to-break, breaking pieces 21 connected to the locking cylinder 22so that the outer cap 15 can be screwed on the inner cap 2.

[0110] When the bottle cap unit 1 is opened for the first time, theflexible flaps 28 locks together with the first locking part 5 fromunderside without fail, and prevents the locking cylinder 22 from goingupward. As shown in FIG. 12, the breaking pieces are surely broken, andthe locking cylinder 22 falls in a reliable way without being interferedby the neck ring 26.

[0111] Sixth Embodiment

[0112] In the sixth embodiment shown in FIGS. 13 and 14, the secondlocking part is disposed on the locking cylinder 22 of the outer cap 15,and consists of multiple, flexible flaps 28, which can be extendedobliquely upward and inward from the lower edge of the locking cylinder22.

[0113] As shown in FIG. 13, when the outer cap 15 is screwed on theinner cap 2 provided with the hooking edge 6 in the lower, outer portionof the attaching cylinder 3, the flexible flaps 28 change theirpositions flexibly, climb over the first locking part 5 easily, andallow the outer cap 15 to be screwed on the inner cap 2.

[0114] When the breaking pieces 21 are broken as shown in FIG. 14, theflaps 28 securely lock with the first locking part 5 from underside toprevent the locking cylinder 22 from ascending. The breaking pieces 21are thus broken without fail, and the locking cylinder 22 falls withoutinterference of the neck ring 26 down to the position at which thelocking cylinder 22 is stopped by the hooking edge 6. At that position,the locking cylinder 22 holds back the attaching cylinder 3 from outsideand helps the inner cap 2 remaining fitted stably onto the bottleneck24. At the same time, the locking cylinder 22 covers the gap formedbetween the attaching cylinder 3 and the neck ring 26, and thereby makesit impossible to pick the inner cap 2 unjustly out of the bottleneck.

[0115] When the bottle cap unit 1 is removed from the bottleneck 24 forseparate collection, a pulling force is acted on the locking cylinder 22in the downward direction, as shown in FIG. 14 by a chain double-dottedline, to release the flexible flaps 28 from the weak engagement with thehooking edge 6 and to allow the locking cylinder 22 to fall down to thelimit of fall. Then, the bottle cap unit can be snapped out of thebottleneck 24 by grasping the inner cap 2 with a hand and wrenching itaway.

INDUSTRIAL AVAILABILITY

[0116] As described above, this invention makes it impossible to pickthe synthetic resin bottle cap unit unjustly out of the bottleneck, andenables the synthetic resin bottle cap unit to be snapped easily out ofthe bottleneck for separate collection.

1. A synthetic resin bottle cap unit comprising an inner cap having anattaching cylinder which is tightly fitted around bottleneck and islocked by climbing over the neck to form a pour spout, and acylindrical, flat-topped outer cap, which is detachably screwed on oroff the inner cap to close or open the pour spout, said attachingcylinder of the inner cap being provided with the first locking partdisposed on outer cylindrical wall of the portion opposed to the lockingpart of the bottleneck, and said outer cap being provided with an outercylinder, which is fitted around the attaching cylinder under the closedstate, and being provided with a locking cylinder disposed in the lowerportion of the outer cylinder and integrally connected thereto throughmultiple breaking pieces, said locking cylinder having a bore diameterlarger than the outer diameter of neck ring and having the secondlocking part that goes into the locking engagement from underside withthe first locking part, wherein the attachment of the inner cap to thebottleneck is set at such a strength that the inner cap can be manuallysnapped out of the bottleneck, and yet said strength being within arange enough to keep the inner cap fitted tightly to the bottleneck butnot to allow the inner cap to be slipped out of the bottleneck becauseof a water-hammer force of the liquid content nor to allow the inner capto move freely around the neck.
 2. A synthetic resin bottle cap unit,comprising an inner cap having an attaching cylinder, which is tightlyfitted around bottleneck and is locked by climbing over the neck to forma pour spout, and a cylindrical, flat-topped outer cap, which isdetachably screwed on or off the inner cap to close or open the pourspout, said attaching cylinder of the inner cap being provided with thefirst locking part disposed on outer cylindrical wall of the portionopposed to the locking part of the bottleneck and also being providedwith a hooking edge slightly projected laterally from the lower edge ofthe attaching cylinder, and said outer cap being provided with an outercylinder, which is fitted around the attaching cylinder under the closedstate, and with a locking cylinder disposed in the lower portion of theouter cylinder and integrally connected thereto through multiplebreaking pieces, said locking cylinder having a bore diameter largerthan the outer diameter of this neck ring and having the second lockingpart that goes into a tight locking engagement from underside with thefirst locking part and into a light locking engagement from upper sidewith the hooking edge, wherein the attachment of the inner cap to thebottleneck is set at such a strength that the inner cap can be manuallysnapped out of the bottleneck, and yet said strength being within arange enough to keep the inner cap fitted tightly to the bottleneck butnot to allow the inner cap to move freely around the neck.
 3. Thesynthetic resin bottle cap unit according to claim 1 or 2, wherein thestrength of attachment of the inner cap to the bottleneck is set bymeans of the thickness of the attaching cylinder.
 4. The synthetic resinbottle cap unit according to claim 1 or 2, wherein the strength ofattachment of the inner cap to the bottleneck is set by means ofexpanding slots disposed at least in the lower portion of the attachingcylinder.
 5. The synthetic resin bottle cap unit according to claim 1,2, 3, or 4, wherein the locking cylinder of the outer cap has a heightranging from the level of the first locking part to the neck ring of thebottleneck
 6. The synthetic resin bottle cap unit according to claim 1,2, 3, 4, or 5, wherein the first locking part has a simple ridgestructure.
 7. The synthetic resin bottle cap unit according to claim 1,2, 3, 4, 5, or 6, wherein the second locking part is a circumferentialridge, which is disposed on the inner surface of the locking cylinderand is capable of climbing over the first locking part.
 8. The syntheticresin bottle cap unit according to claim 1, 2, 3, 5, 6, or 7, whereineither or both of the first locking part and the second locking parthave an intermittent, circumferential ridge structure.
 9. The syntheticresin bottle cap unit according to claim 1, 2, 3, 4, 5, or 6, whereinthe second locking part consists of multiple, flexible flaps, which arecapable of elastic displacement to extend obliquely upward and inwardfrom the lower edge of the locking cylinder.
 10. The synthetic resinbottle cap unit according to claim 1, 2, 3, 4, 5, 6, 7, 8, or 9, whereina space enabling the periphery of a coin to enter therein is formedbetween the neck ring and the lower edge of the attaching cylinder. 11.The synthetic resin bottle cap unit according to claim 1, 2, 3, 4, 5, 6,7, 8, 9, or 10, wherein the minimum bore diameter of the lockingcylinder including the second locking part is set at a value larger thanthe outer diameter of the neck ring.
 12. The synthetic resin bottle capunit according to claim 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, or 11, whereinthe inner cap is colored differently from the outer cap.
 13. Thesynthetic resin bottle cap unit according to claim 1, 2, 3, 4, 5, 6, 7,8, 9, 10, 11, or 12, wherein the pour spout of a pull-open type isformed in the inner cap to guide the flow of the liquid content and isopened by pulling up a pull ring and the like to break open a lidportion zoned by a breaking groove that forms a closed loop surroundinga sealing lid, which is the bottom of the pour spout.
 6. (Amended) Thesynthetic resin bottle cap unit according to claim 1, wherein the firstlocking part has a simple ridge structure.
 7. (Amended) The syntheticresin bottle cap unit according to claim 1, wherein the second lockingpart is a circumferential ridge, which is disposed on the inner surfaceof the locking cylinder and is capable of climbing over the firstlocking part.
 8. (Amended) The synthetic resin bottle cap unit accordingto claim 1, wherein either or both of the first locking part and thesecond locking part have an intermittent, circumferential ridgestructure.
 9. (Amended) The synthetic resin bottle cap unit according toclaim 1, wherein the second locking part consists of multiple, flexibleflaps, which are capable of elastic displacement to extend obliquelyupward and inward from the lower edge of the locking cylinder. 10.(Amended) The synthetic resin bottle cap unit according to claim 1,wherein a space enabling the periphery of a coin to enter therein isformed between the neck ring and the lower edge of the attachingcylinder.
 11. (Amended) The synthetic resin bottle cap unit according toclaim 1, wherein the minimum bore diameter of the locking cylinderincluding the second locking part is set at a value larger than theouter diameter of the neck ring.
 12. (Amended) The synthetic resinbottle cap unit according to claim 1, wherein the inner cap is coloreddifferently from the outer cap.
 13. (Amended) The synthetic resin bottlecap unit according to claim 1, wherein the pour spout of a pull-opentype is formed in the inner cap to guide the flow of the liquid contentand is opened by pulling up a pull ring and the like to break open a lidportion zoned by a breaking groove that forms a closed loop surroundinga sealing lid, which is the bottom of the pour spout.